Wire enameling die



NOV 20, 1951 R. H. DENHAM WIRE ENAMELING DE Filed Feb. 27. 1948Inventor: y'Robert H. Denham,

His Att orneg.

Patented Nov.. 1951 2,515,911 wma ENAMELmo nm Robert H. Denham, Scotia,N. Y., assigner to General Electric (lompany,` a, corporation of NewYork Application February 21, lua'serm No. 11,591

11 claims. l

This invention relates to dies for coating wire, cable, textile threadsand the like having a circular cross section. More especially it relatesto dies having a non-circular die opening for uniformly coating round orcircular wire with an enamel, varnish or lacquer and is of particularinterest when used with coating materials applied in a highly viscousstate.

Normally, round wires are coated using a die having a round hole ofsuiiicient clearance to pass the desired thickness of enamel or coatingmaterial. In order lto promotea more uniform deposition of material theround wire after passing through the viscous coating material is drawnvertically through the round die opening. However no adequate means hasyet been devised to hold the wire in the center of this round opening toassure concentricity of the enamel film. Moreover, all such prior artdies whether of the type through which the wire passes vertically or ofthe type through which the wire passes horizontally are complicated instructure and therefore expensive to manufacture and maintain.

It is therefore an object of my invention to provide a die which willresult in circular coated wire, cable and the like having a concentriccoating or film" thereon.

It is another object of my invention to provide dies which will centerround wire as it passes therethrough.

It is still a further object of my invention to provide supporting meansfor dies which permit full floating suspension of the dies supportedthereon.

It is also an object of my invention to provide an improved constructionand arrangement of dies which is simple in construction, cheap tomanufacture and effective in operation.

In accordance with my invention, I provide, for circular wire, anon-circular die opening dened by a plurality of equally spaced wirecen-l tering points lying on the circumference of a circle having adiameter approximately equal to the diameter of the circular wire beingcoated which points are interconnected by surfaces lyscope of myinvention will be pointed out in the appended claims. In the drawingFig.. l illustrates an apparatus partially in section for enameling wireincluding a die embodying my invention; Fig. 2 is an enlarged side orelevation view of the die' of Figure 1 including the supporting meanstherefor; Fig. 3 is a plan view of the die and support of Fig. 2; Fig. 4illustrates a side view of a modified `type of support for the die; Fig.5 is a plan view of the Fig. 4l support; Fig. 6 is an elevation view ofthe support taken on the line 8-6 of Fig. 4; Fig. 'I is an enlargedplane view of the die proper illustrating one shape of die openingincorporating my invention and Fig. 8 is an enlarged plan view of thedie proper illustrating another shape of die opening.

The enameling or coating apparatus shown in Fig. 1 comprises a containerI for viscous coating material 2. Round or circular wire I to be coatedis drawn from a pay-od reel 4 over a guide sheave 5 immersed within theliquid coating material 2, The wire leaves the container 'I with itssurfaces coated with a non-uniform layer of coating material. In orderto uniformly and concentrically spread the coating material over thewire and to remove excessive coating material therefrom the wire passesvertically through a die B fioatingly supported on a support 1 rigidlysecured to the lower end of a baking oven 8. The latter has spacedparallel walls 9 and Ill and in the present example is heated by aplurality of electric heating elements II disposed within recesses ofthe walls 9 and III. A channel IZ/for the admission of air to the ovenis formed in the wall 9. On its passage through the oven, the coatingmaterial is baked and in many instances the wire ls provided withseveral coatings. The wire therefore with its heat-hardend insulatedcoating of enamel thereon is passed over a driving sheave I3 and thenrecirculated through the coating material, additionalV dies havingprogressively larger openings therein, and the oven and upon baking ofthe last coating the wire is wound onto a take-up reel Il.

'I'he die support illustrated in Figures 2 and 3 comprises a pair ofparallel fingers or rods I5 and I6 respectively supported by theseparate parts of split block I8. Block I8 is maintained assembled aboutthe enlarged cylindrical portion of a shoulder screw I9 by the biasingaction of a resilient U-shaped springlll which partially encirclesblockl I8 and exerts its biasing action in vertical slots in the sidewalls thereof. Shoulder screw I 9 is screwed into a tapped opening inL-shaped block 2| so that the shoulder of the Y screw is tightly boundby the thread engagement against the upper surface of block 2 I. Thelength of the enlarged cylindrical portion of .screw I9 is slightlygreater than the thickness of block I8 so that as thus assembled blockI8 and rods I5 and I8 are free to rotate in a horizontal plane about thevertical axis of screw I9. L-shaped block 2| is in turn rigidly fixed tosupport 1 in any Isuitable manner such as by screw 22.

The die proper comprises a pair of cylindrical rollers 23 and 24 each ofwhich has in the periphery thereof an identical annular groove havingthe shape of half a polygon such as half a square 25, more clearly-shown by Fig. '7, or half a hexagon 28 illustrated by Fig. 8. Rollers23 and 24 are respectively mounted on rods I5 and I8 and biased intocontact, as shown. bythe biasing action of U-shaped spring 20 so thatthe matched grooves therein will form an enclosed die opening having theshape of a full polygon-as shown by Figure 7 or 8. 'I'he dimensions ofthe grooves are selected so that the minimum cross sectional dimension aof the enclosed opening will be approximately equal to the diameter ofthe circular wire or cable while the maximum cross sectional dimension bwill be greater than the diameter of the wire. Thus the wire in passingthrough the die is centered in the die opening by the die itself whileexcess coating'material is removed from the wire with the exception offour beads, in the case of a square die opening, or 6 beads, in the caseof a hexagonal die opening which I have found distribute themselvesthereafter equally around the wire by surface tension wherebyconcentricity of the enamel film is assured. At this point it should beobserved that the enclosed polygonal die openings illustrated areregular such as ya squareor a hexagon havlng equal sides and angles.'I'he volume or cross sectional area of the beads of material on thewire permitted to pass through the die opening are thus equal whichfurther assures concen.

tricity. It should also be observed that a pair of opposite angles ofthe enclosed polygon are formed by sides which intersect on the line ofings so lon'g as the cross sectional shape thereof is defined by aplurality of equally spaced centering points lying on the circumferenceof a circle approximately equal in diameter to the circular wire beingcoated which points are interconnected by surfaces lying outside thecircumference to allow for passage of the beads of coating material.However, as previously pointed out, shapes other than the simple squareor hexagon would probably considerably increase the manufacturing costof the die.

The inside diameter of rollers 23 and 24 is slightly greater than thediameter of rods I5 and I8 so that the rollers are both rotatably andslidably mounted thereon. Thus, to allow for whipping or lateral motionof wire 3 as it passes between sheaves 5 and I3 the support permits notonly free rotary motion of the rods and roll- Although I haveillustrated polygonal..

. allowed by the free slidable motion of the legs ers about screw I9 butfree axial movement of the rollers along the rods is permitted as well.

. 4 ures 4, 5 and 6 comprises a relatively stiff but resilient hair pinshaped rod 21 upon the legs 28 and 29 of which the rollers 23 and 24 arerespectively mounted. The rollers are maintained in contact by theinherent biasing action of the two parallel legs toward each other. Forsup-- port of the hair pin shaped rod 21 so that the axis of the legsthereof will be in a horizontal plane, a pin is provided having aportion of reduced diameter 30 for insertion into an opening of support3I which in turn may be rigidly mounted in any suitable manner on thewall of baking oven 8. At its upper end, the pin terminates in aT-shaped portion the transverse part 32 of which has a length equal tothe maximum diameter of the pin and the longitudinal part 33 of whichhas a length slightly greater than the diameter of hair pin shaped rod21. Adjacent the lower end of the pin, a transverse opening therethroughnormal to the broad dimension of the T part at the upper end of the rodis provided into which a key or pin 34 is inserted. Rotary motion of thesupport pin within the opening of support 3I is resiliently prevented bythe upward biasing action of spring 35 inserted between the 'shaped part90 to the position indicated in Fig-5.

The rod 21 will thereafter be held between the -upper surface of collar36 and the lower surfaces oi' the transverse portion 32 and inasmuch asthe longitudinal part 33 of the T-shaped portion has a length slightlygreater than the diameter of the rodv 21, the legs 28 and 29 thereofwill be free to slide axially, in contrast to the y main embodiment, aswell as free to rotate about the longitudinal part of the T-shapedportion as a vertical axis. If desired, rollers 23 and 24 may be ilxedin any suitable manner on the legs 28 and 29 so as not to have slidablemotion thereon but lateral movement of the rollers with the wire,passing therebetween, will nevertheless be proper. On the other handrollers 23 and 24 may be both rotatably and fslidably mounted on thelegs as in the main embodiment.- 'I'hus a full floating suspension forthe die is provided which is simple, inexpensive and quicklyreplaceable.

While I have, in accordance with the patent statutes, shown a particularembodiment of my invention and modifications thereof, other changes andmodications will be obvious to those skilled in the art and I.therefore, aim in the appended claims to cover all such changes andmodifications as fall within the true spirit and scope of my invention.

What I, claim as new' and desire to secure by Letters Patent of theUnited States is:

l. In an apparatus for coating wire, cable, and like work having acircular cross section, means for uniformly distributing a coating onsaid work of enamel, varnish, or lacquer material by virtue of thesurface tension exhibited by said material including a pair ofcylindrical rollers each of which has in the periphery there- The modiedtype of support illustratedinFgof an identical annular groove having across section defined by a plurality of equally spaced points lyins onthe circumference of a circle interconnected by lines lying outside ofsaid circumference, and means including a support shaft and a pair ofspaced rods rotatably supported thereon for respectivelysupporting saidrollers in contact-.relationship so that the axes thereof will beparallel, lie in a common horizontalplane and the 'matched groovestherein will form an enclosed die opening having a maximum crosssectional dimension greater than the work being coated and a minimumcross sectional dimension at least equal to the work being coated.

2. In an apparatus for coating wire, cable, and

like work having a circular cross section, means `ference, meansincluding a support shaft and a pair of spaced rods rotatably supportedthereon,

said rollers being respectively mounted on saidv rods whereby the axesof said rollers are main-A tained parallel and in the same horizontalplane and resilient biasing means to force said rollers toward eachother so that the matched grooves therein will form an enclosed dieopening lying in a horizontal plane and having a minimum,

cross-sectional dimension at least equal to the work being coated.

3. In an apparatus for coating wire, cable, and like work having acircular cross section,

means for uniformly distributing a coating on` said work of enamel,varnish or lacquer material by virtue of the surface tension exhibitedby said material including a support pin, a pair of spaced and parallelrods the axes of which lie in the same horizontal plane, rotatablymounted on'said pin, a pair of cylindrical rollers each of which has inthe periphery thereof an identical annular groove the cross section ofwhich is defined by a plurality of spaced points lying on thecircumference of a circle interconnected by lines lying outside saidcircumference. each of said rollers respectively mounted on vsaid rodswith the grooves therein in alignment, and resilient biasing means toforce said rods and said rollers toward each other so that the matchedgrooves therein will form an enclosed die opening lying in a horizontalplane, said enclosed opening having a maximum cross sectional dimensiongreater than the work being coated and a minimum cross sectionaldimension at least equal to the work being coated.

4. In an apparatus for coating wire, cable, and like work having a roundcross section, means for uniformly distributing a coating on said workof enamel, varnish, or lacquer material by virtue of the surface tensionexhibited by said material including a pair of cylindrical rollers eachof which has in the periphery thereof an identical annular groove havingthe shape of half a polygon,'a vertically disposed support pin, a pairof spaced rods rotatably supported on said pin, said rollers beingrespectively mounted on said rods whereby the axes of said rollers aremaintained parallel and in the same horizontal plane and resilientbiasing means to force said rollers in contact so that the matchedgrooves therein i will form an enclosed horizontal die opening havingthe shape of a polygon with a maximum cross sectional dimension greaterthan the work being coated and a minimum cross sectional dimension atleast equal to the work being coated.

5. In an apparatus for coating wire cable, and like work having a roundcross section, means for uniformly distributing a coating on said workof enamel, varnish, or lacquer material by virtue of the surface tensionexhibited by said material including a pair of cylindrical rollers eachof which has in the periphery thereof an identical annular groove thecross sectional shape of which is defined by the full sides of half apolygon, a support pin, a pair of spaced rods rotatably supported onsaid pin, said rollers being respectively mounted on said rods wherebythe axes of said rollers are maintained parallel and in the samehorizontal plane Aand resilient biasing means to force said rollers intoco- Y operative rolling contact so that the matched grooves therein willform an enclosed horizontal die opening therebetween having the shape ofa polygon a pair of opposite angles of which are formed by sidesintersecting on the line of contact of said rollers, said enclosed dieopening having a minimum cross-sectional dimension at least equal to thework being coated.

Y 6. In an apparatus for coating wire, cable, and like work having acircular cross section, a pair of spaced and parallel rods rotatablymounted so that said pair of rods will be supported in parallel andspaced relationship with the axes thereof in a common horizontal planeand will be free to rotate about a common vertical axis, means foruniformly distributing a coating on said work including a pair ofcylindrical rollers each of which has in the periphery thereof anidentical annular groove having the shape of half a polygon, each ofsaid rollers respectively mounted rotatably and slidably on said rods sothat the grooves therein may be aligned and resilient biasing means toforce said rollers in contact so that the matched grooves therein willform an enclosed die opening therebetween having the `shape of apolygon, said enclosed opening having a maximum cross sectionaldimension greater than the work being coated and a minimum crosssectional dimension at least equal to the work being coated.

7. In an apparatus for coating wire, cable, and like work having a roundcross section, means for uniformly distributing a coating on said workincluding a pair of cylindrical rollers each of which has in theperiphery thereof an identical annular groove having the shape of half apolygon, said rollers respectively mounted on the legs of a resilienthair pin shaped rod the legs of which are inherently biased toward eachother to force said rollers in contact so that the matched groovestherein will form an enclosed die opening having the shape of a polygonwith a maximum cross sectional dimension greater than the work beingcoated and a minimum cross sectional dimension at least equal to thework being coated, said hair pin shaped rod being slidably and rotatablymounted with the axes of the legs in a common horizontal plane so thatsaid legs will be free to both slide axially and rotate about a verticalaxis.

8. In an apparatus for coating wire, cable, and like work having lacircular cross section, means for uniformly distributing a coating onsaid work of enamel, varnish, or lacquer material by virtue of thesurface tension exhibited by said material including a pair ofcylindrical rollers each of which has in the periphery thereof anidentical annular groove the cross sectional shape of which is definedby the full sides of half a square and means including a support and apair of spaced rods rotatably supported thereon for supporting saidrollers in contact relationship so that the axes of said rollers will beparallel and the matched grooves therein will form an enclosedhorizontal die opening therebetween having the shape of a square a pairof opposite angles of which are formed by sides intersecting on the lineof contact of said rollers, said enclosed opening having a minimumcross-sectional dimension 'at least equal to the work being coated.

9. In an apparatus for coating wire, cable, and like work having acircular cross section, means for uniformly distributing a coating onsaid work of enamel, varnish, or lacquer material by virtue of thesurface tension exhibited by said material including a pair ofcylindrical rollers each of which has in the periphery thereof anidentical annular groove the cross sectional shape of which is definedby the full sides of half a hexagon and means including a support and apair Voi? spaced rods rotatably supported thereon for supporting saidrollers in contact relationship so that the axes of said rollers will beparallel and the matched grooves therein will form an enclosedhorizontal die opening therebetween having the shape of-a hexagon a pairof opposite angles of which are formed by sides intersecting on the lineof contact of said rollers, said enclosed die opening having a minimumlcrosssectional dimension at least equal to the work being coated.

10. In an apparatus for coating wire, cable, and like work having around cross section. means for uniformly distributing a coating on saidwork including a pair of cylindrical rollers each of which has in theperiphery thereof an identical annular groove the cross sectional shapeof which is defined by the full sides of half a square, said rollersrespectively mounted on the legs of a resilient hair pin shaped rod thelegs of which are inherently biased toward each other to force saidrollers into cooperative rolling contact so that the matched groovestherein will form an enclosed die opening therebetween having the shapeof a square a pair vof opposite angles of which are formed by sidesintersecting on the line of contact of said rollers, said hair pinshaped rod being slidably and rotatably mounted with the axes of thelegs in a common horizontal plane so that said legs will be free to bothslide axially and rotate about a vertical axis.

11. In an apparatus for coating wire, cable, and like work having around cross section means for uniformly distributing a coating on saidwork including a pair of cylindrical rollers each of which has in theperiphery thereof an identical annular groove the cross sectional shapeof which is defined by the full sides of half a hexagon, said rollersrespectively mounted on the legs of a resilient hairpin shaped rod thelegs of which are inherently biased toward each other to force saidrollers into cooperative rolling contact so that the matched groovestherein will form an enclosed die opening therebetween having the shapeof a hexagon a pair of opposite angles of which are formed by sidesinter-V secting on the line of contact of said rollers, said hair pinshaped rod being slidably and rotatably mounted ,with the axes of thelegs in a common horizontal plane so that said legs will be free to bzglslide axially and rotate about a vertical a ROBERT H. BENI-IAM.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 270,709 Wardwell Jan. 16, 18831,759,850 Janicki' May 27, 1930 1,957,942 Convers May 8, 1934 2,287,589Wilson et al. June 23, 1942 2,433,642 Bailey Dec. 30, 1947

